''' Cumulus clouds usually have a puffy
cotton-like appearance, with noticeable vertical development and
clearly defined edges. They can be found alone, in lines, or in
clusters. Factors like instability, moisture, and temperature
gradient, make cumulus clouds precursors of many other types of
clouds, e.g cumulonimbus clouds. In
some cases these clouds can be associated with dust devils,
landspouts, waterspouts and tornadoes. Cumulus means heap or
a pile in Latin.

Formation

Cumulus clouds are formed when air rises and
reaches a level where the moisture in the air condenses. This is
usually through convection where a parcel of air is warmer than the
surrounding air. As it rises, the air cools at the dry adiabatic
lapse
rate (approximately 3°C per 1000ft or 1°C per 100m), while the
dewpoint of the air
falls by 0.5°C per 1000ft. When the temperature of the air reaches
the dewpoint, water condenses out of the air to form a cloud. The
size of the cloud depends on the temperature profile of the
atmosphere and the presence of any inversion.
If the top of the cumulus cloud is above the freezing
level, then precipitation
from the cloud is possible.

In windy conditions, the clouds can form lines
(Cloud
streets) parallel with the wind. In mountainous areas, they can
also form lines across the wind due to the presence of lee waves above
the clouds.

Over the sea, cumulus clouds may be found in
regularly spaced lines. The best examples of these lines are found
in the trade winds
where they extend for many miles. These lines create a pattern in
the vertical movement of air, causing it to roll horizontally.
Between the lines of cloud are stronger, more gusty, and slightly
veering winds; but beneath the lines of cloud, somewhat lighter and
more backing winds prevail.

The height at which the cloud starts to form
(cloud
base), depends on the amount of moisture in the air parcel that
forms the cloud. In temperate areas, the base of the cumulus clouds
is usually up to 8,000ft (2,400m). In arid and mountainous areas,
the cloudbase can be in excess of 20,000ft (6,000m).

Glider pilots often
use cumulus clouds as a good indicator of the rising air or
thermal underneath.It is
one of the four clouds (The Cumulus, stratus, cirrus, and
cumulonimbus clouds)